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Sains Malaysiana 55(3)(2026): 375-383
http://doi.org/10.17576/jsm-2026-5503-02
Floral Structures and
Volatile Metabolites of Hoya mcgregorii Schltr.: Revealing Structural Complexity and Metabolite
Distribution
(Struktur Bunga dan Metabolit Meruap Hoya mcgregorii Schltr.: Mendedahkan Kerumitan Struktur dan Taburan Metabolit)
SYAZWANI BASIR1,*, NORAINI TALIP1, AHMAD FITRI
ZOHARI1 & HAMIDUN BUNAWAN2
1Department of Biological
Science and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia,
43600 每日大赛app Bangi, Selangor, Malaysia
2Institute of Systems Biology, Universiti Kebangsaan Malaysia, 43600 每日大赛app Bangi, Selangor, Malaysia
Received:
3 May 2025/Accepted: 20 February 2026
Abstract
Hoya R.Br. is a well-known ornamental genus valued for its distinctive floral morphology and the emission of a wide range of floral scents. However, the structural basis underlying scents production in Hoya flowers remain insufficiently explored. This study focuses on Hoya mcgregorii Schltr and aims to identify and characterise the types and spatial distribution of secretory structures and their associated metabolites through an integrative anatomical, histochemical and phytochemical approach. Using light microscopy, electron microscopy and histochemical staining, two distinct secretory structures were identified: secretory nectaries (sn) located on the corona lobes and unicellular conical shaped glandular trichomes (cgt) distributed along the adaxial epidermis of corolla. Histochemical stanning showed that the sn actively secreted lipids, proteins, starch grains and polysaccharides, while the cgt produced lipid and proteins. Further analysis of the floral scent composition using gas chromatography-mass spectrometry (GC-MS) identified 33 volatile organic compounds (VOCs), with β-ocimene constituting the dominant component (26.23%). These findings show the presence of morphologically and functionally distinct floral glands in H. mcgregoriiand provide new insights into the structural and chemical adaptations involved in scent emission of genus Hoya. Keywords: β-ocimene; Hoya;
nectary; trichome
Abstrak
Hoya R.Br. merupakan salah satu tumbuhan hiasan terkenal kerana morfologi bunganya yang unik dan keupayaanya menghasilkan pelbagai bauan bunga. Walau bagaimanapun, struktur asas dan mekanisme biokimia yang terlibat dalam penghasilan bauan bunga Hoya masih kurang diterokai. Kajian ini memberikan tumpuan kepada Hoya mcgregorii Schltr. bertujuan untuk mengenal pasti dan mencirikan jenis serta taburan reruang struktur rembes dan metabolit berkaitannya melalui pendekatan translasi merangkumi anatomi, histokimia dan fitokimia. Dengan menggunakan mikroskop cahaya, mikroskop elektron dan pewarnaan histokimia, dua struktur rembes yang berbeza telah dikenal pasti: sekretori nektari (sn) yang terletak pada bahagian lobus korona dan trikom kelenjar berbentuk kon sel tunggal (cgt) yang dijumpai sepanjang permukaan adaksial epidermis korola. Analisis histokimia menunjukkan bahawa sn secara aktif merembeskan lipid, protein, butiran kanji dan polisakarida, manakala cgt menghasilkan lipid dan protein. Analisis lanjut terhadap komposisi bauan bunga menggunakan kromatografi gas-spektrometri jisim (GC-MS) mengenal pasti 33 sebatian organik meruap (VOCs) dengan kehadiranβ-ocimena dominan (26.23%). Penemuan ini menunjukkan kehadiran struktur rembes yang berbeza dari segi morfologi dan fungsi pada Hoya mcgregoriidan memberi pandangan baharu tentang penyesuaian struktur dan kimia yang terlibat dalam pelepasan bauan bunga genus Hoya. Kata kunci: b-ocimena; Hoya; nektar; trikom
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*Corresponding author;
email: syazwani.basir@ukm.edu.my
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